How can i access parent module from sub module when only sub module is in context of server?

I have one parent module and a sub module in a front end project.Sub module uses parent module through maven dependency.

I already have a unit test case setup for parent module using mocha and all unit test cases have been written.Mocha sets up local server within the context of the module to run the tests

Now I want a similar setup for my sub module to begin writing unit test cases but as my sub module using parent module functions, how can I use parent module file structure as it is out of the context of the local server?

P.S. - I cannot change my folder structure or something similar to this as it is not in my hands.